Susskind wins prestigious Sakurai Prize in theoretical physics

Physics Professor Leonard
Susskind has been named the winner of the 1998 J. J. Sakurai Prize for theoretical particle physics. Awarded annually by the American Physical Society, it is considered one of the top international awards in the field.

The prize, which includes $5,000, will be presented at the annual meeting of the American Physical Society in Columbus, Ohio, on April 21, 1998. According to the citation, Susskind was honored "for his pioneering contributions to hadronic string models, lattice gauge theories, quantum chromodynamics, and dynamical symmetry breaking."

Colleagues say Susskind's hallmark has been the application of "brilliant imagination and originality" to the theoretical study of the nature of the elementary particles and forces that make up the physical world.

A case in point is string theory. For centuries scientists have thought about the basic building blocks of matter as tiny points or spheres. Today, an increasing number of the world's theoretical physics are seriously exploring the possibility that these basic units may be better described as tiny vibrating strings. This theory owes its origin to Susskind and Y. Nambu from the University of Chicago. In 1969 they hit on the idea that the reason why quarks ­ the building blocks for the protons and neutrons found in the nucleus of the atom ­ never appear in isolation is because they are linked by a force that could be described as a string. The idea was later extended to gravitation by John Schwartz of the California Institute of Technology, Joel Scherk of Ecole Normale Superieure in Paris and others. Most recently, a group of mathematical theorists led by Ed Witten at Princeton has developed the concept into an alternate theory for elementary particles called superstring theory.

The growing appeal of superstring theory is the promise it holds of bridging the great rift in modern theoretical physics: the divide between quantum mechanics that accurately describes the motion of subatomic particles and Einstein's theory of relatively that describes the forces that shape cosmic space and time. Contradictions and conflicts between these two highly successful theories have emerged as the major barrier to developing a grand unified theory, or "theory of everything."

In the 1990s, Susskind was a pioneer in extending string theory to the problem represented by black holes, supermassive collapsed objects surrounded by a gravitational field so strong that not even light can escape if it ventures too close. When Cambridge physicist Stephen Hawking raised the possibility that black holes not only siphon up all the matter and light particles in their vicinity, but that they may represent a fundamentally new way that information is permanently lost from the universe, Susskind was one of those who objected to this conclusion. He and Gerard t'Hooft of Utrecht University in the Netherlands calculated that heat given off by black holes would have broiled the entire universe by now if Hawking's premise was correct.

To test this idea, Susskind and several collaborators simulated the behavior of an individual string as it falls into a black hole. This work, along with that of other researchers in the field, helped use string theory to show that information about objects swallowed by black holes does not disappear in a new and particularly permanent fashion as Hawking has suggested. Indeed, the theory confirmed that as black holes grow they suck information out of physical contact behind the black hole's event horizon, the point of no return for physical objects. But once black holes reach a certain size, they begin to evaporate. In so doing, the information that they contain is released, although in a thoroughly mixed-up state.

Two years ago Susskind initiated the formation of a new institute that has helped campus theorists participate more fully in the cutting-edge research in this area. Under his direction, the institute, formed by a grant of $65,000 a year from Gerhard Casper's President's Fund, is bringing visitors to Stanford so that faculty and students have a chance to interact and collaborate with them. "An institute like this is essential," said Gary Gibbons of Cambridge University, who was an early visitor. "No single department has enough expertise to make progress in this field."

Collaborations forged between institute members and visitors, including Steve Shenker and Tom Banks of Rutgers University and Willy Fischler of the University of Texas, have played a major role in one of the hottest subjects in string theory in the last year: the development of a kind of meta-string-theory called Matrix Theory. Although it is not a string theory itself, it integrates a number of different variants of superstring theory that scientists had considered mutually exclusive.

Susskind, who was born in New York City, earned his bachelor of science degree from City College of New York in 1962 and his doctorate from Cornell University in 1965. After a postdoctoral fellowship at the University of California-Berkeley, he joined taught physics at Belfer Graduate School of Science in New York and Tel Aviv University in Israel before coming to Stanford in 1979. He is a recipient of the Pregel Award from the New York Academy of Sciences, and is a member of the American Academy of Arts and Sciences.